Receptacle for pacemaker lead

ABSTRACT

A lead receptacle having a lumen configured to traverse from an outer side of an outermost intercostal muscle to an inner side of an innermost intercostal muscle of an intercostal space of a patient and to support a lead traversing through the lumen. The lumen being configured to support one or more cardiac leads traversing through the intercostal space.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 62/045,683, titled Cardiac Pacemaker Systemhaving Intracostal Electrodes, filed Sep. 4, 2014, U.S. ProvisionalPatent Application No. 62/083,516 titled Implantable Medical Device withPacing Therapy, filed Nov. 24, 2014, and U.S. Provisional PatentApplication No. 62/146,569 titled Delivery Systems and Implantable Leadsfor Intracostal Pacing, filed Apr. 13, 2015, the disclosures of whichare incorporated herein by reference in their entirety.

TECHNICAL FIELD

The subject matter described herein relates to devices, systems andmethods for cardiac pacing.

BACKGROUND

An artificial pacemaker is a medical device that helps control abnormalheart rhythms. A pacemaker uses electrical pulses to prompt the heart tobeat at a normal rate. The pacemaker may speed up a slow heart rhythm,control a fast heart rhythm, and coordinate the chambers of the heart.The implantable portions of a pacemaker system generally comprise threemain components: a pulse generator, one or more wires called leads, andelectrodes found on each lead. The pulse generator produces theelectrical signals that make the heart beat. Most pulse generators alsohave the capability to receive and respond to signals that are sent bythe heart. Leads are insulated flexible wires that conduct electricalsignals to the heart from the pulse generator. The leads may also relaysignals from the heart to the pulse generator. One end of the lead isattached to the pulse generator and the electrode end of the lead ispositioned on or in the heart.

SUMMARY

In one aspect, a lead receptacle is disclosed. The lead receptacle maycomprise a lumen. The lumen may be configured to traverse from an outerside of an outermost intercostal muscle to an inner side of an innermostintercostal muscle of an intercostal space of a patient. The lumen maybe configured to support a lead traversing through the lumen. The lumenmay be configured to support one or more cardiac leads traversingthrough the intercostal space.

In some variations, one or more of the following features may optionallybe included in any feasible combination. The lumen may comprise anelectrically insulating material configured to inhibit traversal ofelectrical signals through walls of the lumen. The intercostal space ofthe patient may be the intercostal space associated with a cardiac notchof the left lung of the patient.

The proximal end of the lumen may be configured to terminate adjacentthe pleural space of the patient, in the mediastinum of the patient, orthe like.

The one or more cardiac leads may be configured to carry electricalstimulation therapy from a pulse generator to a heart of the patient.The one or more cardiac leads may be configured to carry informationfrom one or more sensors disposed in the one or more cardiac leads.

The lead receptacle may comprise at least one flange. The at least oneflange may engage with an inner surface of an intercostal muscle of thepatient. The at least one flange may be adapted to fix the lumen inplace. The lead receptacle may comprise a first flange on a proximal endof the lumen for engaging with an inner surface of an innermostintercostal muscle of the patient. The lead receptacle may comprise asecond flange on a distal end of the lumen for engaging with an outersurface of an outermost intercostal muscle of the patient. The firstflange and the second flange may exert a force inwardly toward themiddle of the lumen configured to fix the lumen in place.

The lumen may be configured to be screwed into an intercostal muscle ofthe patient within the intercostal space, pushed into an intercostalmuscle of the patient within the intercostal space. The lumen may befixed into the intercostal space using a tine, a hook, a spring, ascrew, or the like.

The lumen body may further comprise a septum disposed transverselywithin the lumen, the septum configured to form a seal around the leadtraversing through the lumen.

The lead receptacle can include a second lumen configured to traversefrom an outermost side of an outermost intercostal muscle to aninnermost side of an innermost intercostal muscle. The second lumen maybe adapted to facilitate dispensing pharmacological agents into thethorax of the patient. The lumen may be coated with a pharmacologicalagent.

In another aspect, a method of insulating intercostal muscle from acardiac lead is described. The method may comprise inserting a leadreceptacle into the intercostal space of a patient. The lead receptaclemay comprise a lumen configured to traverse from an outermost surface ofan outermost intercostal muscle to the innermost surface of theinnermost intercostal muscle of the patient. The lumen may be configuredto support a lead traversing through the lumen. The method may comprisefixing the lead receptacle in place in the intercostal space of thepatient.

In some variations, one or more of the following features may optionallybe included in any feasible combination. The method may comprise feedinga distal end of a cardiac lead through the lead receptacle. The methodmay comprise positioning the distal end of the cardiac lead within themediastinum of the patient to deliver electrical stimulation therapy toa heart of the patient. The lumen may be made from an electricallyinsulating material. The lumen may be coated with a pharmacologicalagent.

The details of one or more variations of the subject matter describedherein are set forth in the accompanying drawings and the descriptionbelow. Other features and advantages of the subject matter describedherein will be apparent from the description and drawings, and from theclaims. While certain features of the currently disclosed subject matterare described for illustrative purposes, it should be readily understoodthat such features are not intended to be limiting. The claims thatfollow this disclosure are intended to define the scope of the protectedsubject matter.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, show certain aspects of the subject matterdisclosed herein and, together with the description, help explain someof the principles associated with the disclosed implementations. In thedrawings,

FIG. 1 is a front-view of an exemplary pulse generator having featuresconsistent with implementations of the current subject matter;

FIG. 2 is a rear-view of an exemplary pulse generator having featuresconsistent with implementations of the current subject matter;

FIG. 3 is an illustration of a simplified schematic diagram of anexemplary pulse generator having features consistent withimplementations of the current subject matter;

FIG. 4A is an illustration showing exemplary placements of elements of acardiac pacing system having features consistent with the currentsubject matter;

FIG. 4B is an illustration showing exemplary placements of elements of acardiac pacing system having features consistent with the currentsubject matter;

FIG. 4C is a cross-sectional illustration of a thoracic region of apatient;

FIG. 5 is an illustration of an exemplary method of implanting a cardiacpacing system into a patient having features consistent with the currentsubject matter;

FIG. 6A is an illustration of an exemplary delivery system for a pulsegenerator having features consistent with implementations of the currentsubject matter;

FIG. 6B is an illustration of an exemplary delivery system with a pulsegenerator disposed therein consistent with implementations of thecurrent subject matter;

FIG. 7 is an illustration of an exemplary process flow illustrating amethod of placing a pacing lead having features consistent with thecurrent subject matter;

FIG. 8A is an illustration of an exemplary lead having featuresconsistent with the current subject matter;

FIG. 8B is an illustration of an exemplary lead having featuresconsistent with the current subject matter;

FIG. 9A is an illustration of the distal end of an exemplary deliverysystem having features consistent with the current subject matter;

FIG. 9B is an illustration of an exemplary process for using thedelivery system illustrated in FIG. 9A;

FIG. 10 is a schematic illustration of an exemplary delivery controlsystem having features consistent with the current subject matter;

FIGS. 11A and 11B are illustrations of an exemplary lead having featuresconsistent with the current subject matter;

FIG. 12 is an illustration of an exemplary sheath for delivering a lead,the sheath having features consistent with the current subject matter;

FIG. 13 is an illustration of an intercostal space associated with thecardiac notch of the left lung with an exemplary lead fixationreceptacle having features consistent with the current subject matterinserted therein;

FIG. 14 is an illustration of an exemplary lead fixation receptaclehaving features consistent with the current subject matter;

FIG. 15 is an illustration of an exemplary lead fixation receptaclehaving features consistent with the current subject matter; and,

FIG. 16 is an illustration of an exemplary lead fixation receptaclehaving features consistent with the current subject matter.

When practical, similar reference numbers denote similar structures,features, or elements.

DETAILED DESCRIPTION

Implantable medical devices (IMDs), such as cardiac pacemakers orimplantable cardioverter defibrillators (ICDs), provide therapeuticelectrical stimulation to the heart of a patient. This electricalstimulation may be delivered via electrodes on one or more implantableendocardial or epicardial leads that are positioned in or on the heart.This electrical stimulation may also be delivered using a leadlesscardiac pacemaker disposed within a chamber of the heart. Therapeuticelectrical stimulation may be delivered to the heart in the form ofelectrical pulses or shocks for pacing, cardioversion or defibrillation.

An implantable cardiac pacemaker may be configured to facilitate thetreatment of cardiac arrhythmias. The devices, systems and methods ofthe present disclosure may be used to treat cardiac arrhythmiasincluding, but not limited to, bradycardia, tachycardia, atrial flutterand atrial fibrillation. Resynchronization pacing therapy may also beprovided.

A cardiac pacemaker consistent with the present disclosure may include apulse generator implanted adjacent the rib cage of the patient, forexample, on the ribcage under the pectoral muscles, laterally on theribcage, within the mediastinum, subcutaneously on the sternum of theribcage, and the like. One or more leads may be connected to the pulsegenerator. A lead may be inserted, for example, between two ribs of apatient so that the distal end of the lead is positioned within themediastinum of the patient adjacent, but not touching, the heart. Thedistal end of the lead may include an electrode for providing electricalpulse therapy to the patient's heart and may also include at least onesensor for detecting a state of the patient's organs and/or systems. Thecardiac pacemaker may include a unitary design where the components ofthe pulse generator and lead are incorporated within a single formfactor. For example, where a first portion of the unitary device resideswithin the subcutaneous tissue and a second portion of the unitarydevice is placed through an intercostal space into a location within themediastinum.

FIG. 1 is a front-view 100 of a pulse generator 102 having featuresconsistent with implementations of the current subject matter. The pulsegenerator 102 may be referred to as a cardiac pacemaker. The pulsegenerator 102 can include a housing 104, which may be hermeticallysealed. In the present disclosure, and commonly in the art, housing 104and everything within it may be referred to as a pulse generator,despite there being elements inside the housing other than those thatgenerate pulses (for example, processors, storage, battery, etc.).

Housing 104 can be substantially rectangular in shape and the first endof the housing 104 may include a tapered portion 108. The taperedportion can include a first tapered edge 110, tapered inwardly towardthe transverse plane. The tapered portion 108 can include a secondtapered edge 112 tapered inwardly toward the longitudinal plane. Each ofthe first tapered edge 110 and the second tapered edge 112 may have asimilar tapered edge generally symmetrically disposed on the oppositeside of tapered portion 108, to form two pairs of tapered edges. Thepairs of tapered edges may thereby form a chisel-shape at the first end106 of pulse generator 102. When used in the present disclosure, theterm “chisel-shape” refers to any configuration of a portion of housing104 that facilitates the separation of tissue planes during placement ofpulse generator 102 into a patient. The “chisel-shape” can facilitatecreation of a tightly fitting and properly sized pocket in the patient'stissue in which the pulse generator may be secured. For example, achisel-shape portion of housing 104 may have a single tapered edge, apair of tapered edges, 2 pairs of tapered edges, and the like.Generally, the tapering of the edges forms the shape of a chisel or theshape of the head of a flat head screwdriver. In some variations, thesecond end 114 of the pulse generator can be tapered. In othervariations, one or more additional sides of the pulse generator 102 canbe tapered.

Housing 104 of pulse generator 102 can include a second end 114. Thesecond end 114 can include a port assembly 116. Port assembly 116 can beintegrated with housing 104 to form a hermetically sealed structure.Port assembly 116 may be configured to facilitate the egress ofconductors from housing 104 of pulse generator 102 while maintaining aseal. For example, port assembly 116 may be configured to facilitate theegress of a first conductor 118 and a second conductor 120 from housing104. The first conductor 118 and the second conductor 120 may combinewithin port assembly 116 to form a twin-lead cable 122. In somevariations, the twin-lead cable 122 can be a coaxial cable. Thetwin-lead cable 122 may include a connection port 124 remote fromhousing 104. Connection port 124 can be configured to receive at leastone lead, for example, a pacing lead. Connection port 124 of the cable122 can include a sealed housing 126. Sealed housing 126 can beconfigured to envelope a portion of the received lead(s) and form asealed connection with the received lead(s).

Port assembly 116 may be made from a different material than housing104. For example, housing 104 may be made from a metal alloy and portassembly 116 may be made from a more flexible polymer. While portassembly 116 may be manufactured separately from housing 104 and thenintegrated with it, port assembly 116 may also be designed to be part ofhousing 104 itself. The port assembly 116 may be externalized from thehousing 104 as depicted in FIG. 1. The port assembly 116 may beincorporated within the shape of housing 104 of pulse generator 102.

FIG. 2 is a rear-view 200 of pulse generator 102 showing the back-side128 of housing 104. As shown, pulse generator 102 can include one ormore electrodes or sensors disposed within housing 104. As depicted inthe example of FIG. 2, housing 104 includes a first in-housing electrode130 and a second in-housing electrode 132. The various electrodesillustrated and discussed herein may be used for delivering therapy tothe patient, sensing a condition of the patient, and/or a combinationthereof. A pulse generator consistent with the present disclosureinstalled at or near the sternum of a patient can monitor the heart,lungs, major blood vessels, and the like through sensor(s) integratedinto housing 104.

FIG. 3 is an illustration 300 of a simplified schematic diagram of anexemplary pulse generator 102 having features consistent with thecurrent subject matter. Pulse generator 102 can include signalprocessing and therapy circuitry to detect various cardiac conditions.Cardiac conditions can include ventricular dyssynchrony, arrhythmiassuch as bradycardia and tachycardia conditions, and the like. Pulsegenerator 102 can be configured to sense and discriminate atrial andventricular activity and then deliver appropriate electrical stimuli tothe heart based on a sensed state of the heart.

Pulse generator 102 can include one or more components. The one or morecomponents may be hermetically sealed within the housing 104 of pulsegenerator 102. Pulse generator 102 can include a controller 302,configured to control the operation of the pulse generator 102. Thepulse generator 102 can include an atrial pulse generator 304 and mayalso include a ventricular pulse generator 306. Controller 302 can beconfigured to cause the atrial pulse generator 304 and the ventricularpulse generator 306 to generate electrical pulses in accordance with oneor more protocols that may be loaded onto controller 302. Controller 302can be configured to control pulse generators 304, 306, to deliverelectrical pulses with the amplitudes, pulse widths, frequency, orelectrode polarities specified by the therapy protocols, to one or moreatria or ventricles.

Controller electronic storage 308 can store instructions configured tobe implemented by the controller to control the functions of pulsegenerator 102.

Controller 302 can include a processor(s). The processor(s) can includeany one or more of a microprocessor, a controller, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield-programmable gate array (FPGA), or equivalent discrete or analoglogic circuitry. The functions attributed to controller 302 herein maybe embodied as software, firmware, hardware or any combination thereof.

The pulse generator 102 can include a battery 310 to power thecomponents of the pulse generator 102. In some variations, battery 310can be configured to charge a capacitor. Atrial pulse generator 304 andventricular pulse generator 306 can include a capacitor charged by thebattery 310. The electrical energy stored in the capacitor(s) can bedischarged as controlled by controller 302. The electrical energy can betransmitted to its destination through one or more electrode leads 312,314. The leads can include a ventricular pulsing lead 312, an atrialpulsing lead 314, and/or other leads.

Pulse generator 102 can include one or more sensors 322. Sensor(s) 322can be configured to monitor various aspects of a patient's physiology.Sensor(s) 322 may be embedded in the housing of pulse generator 102,incorporated into leads 312, 314 or be incorporated into separate leads.Sensors 322 of pulse generator 102 can be configured to detect, forexample, signals from a patient's heart. The signals can be decoded bycontroller 302 of the pulse generator to determine a state of thepatient. In response to detecting a cardiac arrhythmia, controller 302can be configured to cause appropriate electrical stimulation to betransmitted through electrodes 312 and 314 by atrial pulse generator 304and/or ventricular pulse generator 306.

Sensor(s) 322 can be further configured to detect other physiologicalstates of the patient, for example, a respiration rate, blood oximetry,and/or other physiological states. In variations where the pulsegenerator 102 utilizes a plurality of electrodes, controller 302 may beconfigured to alter the sensing and delivery vectors between availableelectrodes to enhance the sensitivity and specificity of arrhythmiadetection and improve efficacy of the therapy delivered by theelectrical impulses from the pulse generator 102.

Pulse generator 102 can include a transceiver 316. The transceiver caninclude an antenna 318. The transceiver 316 can be configured totransmit and/or receive radio frequency signals. The transceiver 316 canbe configured to transmit and/or receive wireless signals having anywireless communication protocol. Wireless communication protocols caninclude Bluetooth, Bluetooth low energy, Near-Field Communication, WiFi,and/or other radio frequency protocols. The transceiver 316 can beconfigured to transmit and/or receive radio frequency signals to and/orfrom a programmer 320. The programmer 320 can be a computing deviceexternal to the patient. Programmer 320 may comprise a transceiverconfigured to transmit and/or receive radio frequency signals to and/orfrom the transceiver 316 of the pulse generator 102. Transceiver 316 canbe configured to wirelessly communicate with programmer 320 throughinduction, radio-frequency communication or other short-rangecommunication methodologies.

In some variations, programmer 320 can be configured to communicate withthe pulse generator 102 through longer-range remote connectivitysystems. Such longer-range remote connectivity systems can facilitateremote access, by an operator, to pulse generator 102 without theoperator being in close proximity with the patient. Longer-range remoteconnectivity systems can include, for example, remote connectivitythrough the Internet, and the like. When an operator connects with pulsegenerator 102 through longer-range remote connectivity systems, a localdevice can be positioned within a threshold distance of the patient. Thelocal device can communicate using one or more radio-frequency wirelessconnections with the pulse generator 102. The local device can, in turn,include hardware and/or software features configured to facilitatecommunication between it and an operator device at which the operator isstationed. The local device can be, for example, a mobile computingdevice such as a smartphone, tablet, laptop, and the like. The localdevice can be a purpose-built local device configured to communicatewith the pulse generator 102. The local device can be paired with thepulse generator 102 such that the communications between the pulsegenerator 102 and the local device are encrypted. Communications betweenthe local device and the operator device can be encrypted.

Programmer 320 can be configured to program one or more parameters ofthe pulse generator 102. The parameter(s) can include timing of thestimulation pulses of the atrial pulse generator, timing of thestimulation pulses of the ventricular pulse generator, timing of pulsesrelative to certain sensed activity of the anatomy of the patient, theenergy levels of the stimulation pulses, the duration of the stimulationpulses, the pattern of the stimulation pulses and other parameters. Theprogrammer 320 can facilitate the performance of diagnostics on thepatient or the pulse generator 102.

Programmer 320 can be configured to facilitate an operator of theprogrammer 320 to define how the pulse generator 102 senses electricalsignals, for example ECGs, and the like. The programmer 320 canfacilitate an operator of the programmer 320 to define how the pulsegenerator 102 detects cardiac conditions, for example ventriculardyssynchrony, arrhythmias, and the like. The programmer 320 canfacilitate defining how the pulse generator 102 delivers therapy, andcommunicates with other devices.

An operator can fine-tune parameters through the programmer 320. Forexample, the sensitivity of sensors embodied in the housing of the pulsegenerator 302, or within leads, can be modified. Programmer 320 canfacilitate setting up communication protocols between the pulsegenerator 102 and another device such as a mobile computing device.Programmer 320 can be configured to facilitate modification of thecommunication protocols of the pulse generator 102, such as addingsecurity layers, or preventing two-way communication. Programmer 320 canbe configured to facilitate determination of which combination ofimplanted electrodes are best suited for sensing and therapy delivery.

Programmer 320 can be used during the implant procedure. For example,programmer 320 can be used to determine if an implanted lead ispositioned such that acceptable performance will be possible. If theperformance of the system is deemed unacceptable by programmer 320, thelead may be repositioned by the physician, or an automated deliverysystem, until the lead resides in a suitable position. Programmer 320can also be used to communicate feedback from sensors disposed on theleads and housing 104 during the implant procedure.

In some cases, concomitant devices such as another pacemaker, an ICD, ora cutaneous or implantable cardiac monitor, can be present in a patient,along with pulse generator 102. Pulse generator 102 can be configured tocommunicate with such concomitant devices through transceiver 316wirelessly, or the concomitant device may be physically connected topulse generator 102. Physical connection between devices may beaccomplished using a lead emanating from pulse generator 102 that iscompatible with the concomitant device. For example, the distal end of alead emanating from pulse generator 102 may be physically andelectrically connected to a port contained on the concomitant device.Physical connection between devices may also be accomplished using animplantable adaptor that facilitates electrical connection between thelead emanating from pulse generator 102 and the concomitant device. Forexample, an adapter may be used that will physically and electricallycouple the devices despite not having native components to facilitatesuch connection. Concomitant devices may be connected using a “smartadapter” that provides electrical connection between concomitant devicesand contains signal processing capabilities to convert signal attributesfrom each respective device such that the concomitant devices arefunctionally compatible with each other.

Pulse generator 102 can be configured to have a two-way conversation ora one-way conversation with a concomitant device. Controller 302 can beconfigured to cause the concomitant device to act in concert with pulsegenerator 102 when providing therapy to the patient, or controller 302can gather information about the patient from the concomitant device. Insome variations, pulse generator 102 can be configured to be triggeredvia one-way communication from a concomitant device to pulse generator102.

FIGS. 4A and 4B are illustrations showing exemplary placements ofelements of a cardiac pacing system having features consistent with thepresent disclosure. Pulse generator 102 can be disposed in a patient,adjacent an outer surface of ribcage 404. For example, pulse generator102 can be disposed on the sternum 402 of the patient's ribcage 404. Alead 414, attached to pulse generator 102, may also be disposed in thepatient by traversing through intercostal muscle 410 of the patient.Lead 414 may optionally pass through a receptacle 408 in intercostalmuscle 410 to guide the lead, fix the lead, and/or electrically insulatethe lead from the tissue of the intercostal muscle 410 (examples of suchreceptacles are described herein with respect to FIGS. 13-16).

In other variations, pulse generator 102 can be disposed outside of apatient's ribcage in a pectoral position, outside of the patient'sribcage in a lateral position, below (inferior to) the patient's ribcagein a subxiphoid or abdominal position, within the patient's mediastinum,or the like.

Lead 414 may be passed through the ribcage so the distal end of the leadand its electrodes are disposed on, or pass through, the inner surfaceof the rib or inner surface of the innermost intercostal muscle, or mayalternatively traverse further within the thoracic cavity, but withoutphysically contacting the tissue comprising the heart. This placementmay be referred to herein as intracostal or intracostally.

Leads may be inserted between any two ribs within the thoracic cavity,for example, as shown in FIG. 4A. In some variations, it is desirable toinsert the lead through one of the intercostal spaces associated withcardiac notch of the left lung 420. For example, between the fourth andfifth ribs or between the fifth and sixth ribs. Due to variations inanatomy, the rib spacing associated with the cardiac notch of the leftlung 420 may differ. In some patients the cardiac notch of the left lung420 may not be present or other cardiac anomalies such as dextrocardiamay require the insertion through alternative rib spaces. Lead 414 maybe inserted into such a location through an incision 406, as shown inFIG. 4A. Lead 414 may optionally be inserted into such a locationthrough a receptacle 408, as shown in FIG. 4B.

Precise placement of a distal end of lead 414, which may includeelectrode(s) for pacing or sensing, is now described further withreference to the anatomical illustrations of FIGS. 4A, 4B and 4C. Insome variations, the distal end of lead 414 can be located within theintercostal space or intercostal muscle 410. In such variations, thedistal end of lead 414 is preferably surrounded by a receptacle 408 thatelectrically insulates the distal end of the lead 414 from theintercostal muscle 410. In another variation, the distal end of lead 414may be placed just on the inner surface of a rib or on the inner surfaceof the innermost intercostal muscle.

The distal end of lead 414 can also be positioned so as to abut theparietal pleura of the lung 426. In other variations, the distal end oflead 414 can be positioned so as to terminate within the mediastinum 428of the thoracic cavity of the patient, proximate the heart 418, but notphysically in contact with the heart 418 or the pericardium 432 of heart418. Alternatively, the distal end of lead 414 can be placed to abut thepericardium 432, but not physically attach to the epicardial tissuecomprising the heart.

The distal end of lead 414 may be physically affixed to cartilage orbone found within the thoracic cavity, for example, to a rib, tocartilage of a rib, or to other bone or cartilage structure in thethoracic cavity. In one variation, the lead can be disposed such that itis wrapped around the patient's sternum 402.

For certain placements, lead 414 can be adequately fixed by directphysical contact with surrounding tissue. In other variations, anadditional fixation mechanism may be used. For example, the distal endof lead 414 can incorporate a fixation mechanism such as a tine, hook,spring, screw, or other fixation device. The fixation mechanism can beconfigured to secure the lead in the surrounding tissue, cartilage,bone, or other tissue, to prevent the lead from migrating from itsoriginal implantation location.

FIG. 5 is an illustration 500 of an exemplary method of implanting acardiac pacing system into a patient consistent with the presentdisclosure. At 502, a pulse generator 102 may be implanted, in a mannerdescribed above, adjacent the sternum 402 of a patient. Optionally,pulse generator 102 may be at least partially chisel-shaped tofacilitate implantation and the separation of tissue planes. At 504, alead 414 may be inserted into an intercostal space 410 of a patient. Asdescribed above, lead 414 may optionally be inserted into a receptacle408 disposed within intercostal space 410. At 506, the distal end oflead 414 is delivered to one of a number of suitable final locations forpacing, as described above.

FIG. 6A is an illustration 600 of a pulse generator delivery system 602for facilitating positioning of pulse generator 102 into a patient, thedelivery system 602 having features consistent with the current subjectmatter. FIG. 6B is an illustration 604 of the delivery system 602 asillustrated in FIG. 6A with the pulse generator 102 mounted in it.Delivery system 602 can be configured to facilitate implantation of thepulse generator 102 into the thoracic region of a patient.

Delivery system 602 includes a proximal end 606 and a distal end 608.The distal end 608 of delivery system 602 contains a receptacle 610 inwhich the housing of the pulse generator 102 is loaded. Where the pulsegenerator 102 contains a connection lead, the delivery system 602 can beconfigured to accommodate the connection lead so that the connectionlead will not be damaged during the implantation of the pulse generator102.

When pulse generator 102 is fully loaded into delivery system 602, pulsegenerator 102 is substantially embedded into the receptacle 610. In somevariations, a portion of the pulse generator 102's distal end can beexposed, protruding from the end of receptacle 610. The tapered shape ofthe distal end 106 of pulse generator 102 can be used in conjunctionwith the delivery system 602 to assist with separating tissue planes asdelivery system 602 is used to advance pulse generator 102 to itsdesired location within the patient.

In some variations, the entirety of pulse generator 102 can be containedwithin receptacle 610 of the delivery system 602. The pulse generator102 in such a configuration will not be exposed during the initialadvancement of delivery system 602 into the patient. The distal end 608of delivery system 602 may be designed to itself separate tissue planeswithin the patient as delivery system 602 is advanced to the desiredlocation within the patient.

The pulse generator delivery system 602 may be made from a polymer, ametal, a composite material or other suitable material. Pulse generatordelivery system 602 can include multiple components. Each component ofthe pulse generator delivery system 602 can be formed from a materialsuitable to the function of the component. The pulse generator deliverysystem 602 can be made from a material capable of being sterilized forrepeated use with different patients.

Pulse generator delivery system 602 may include a handle 612. Handle 612can facilitate advancement of delivery system 602 and pulse generator102 into a patient's body. Handle 612 can be disposed on either side ofthe main body 614 of the delivery system 602, as illustrated in FIGS. 6Aand 6B. In some variations, handle 612 can be disposed on just one sideof the main body 614 of the delivery system 602. The handle 612 can beconfigured to be disposed parallel to plane of insertion and advancement616 of pulse generator delivery system 602 within the body. In somevariations, handle 612 can be located orthogonally to the plane ofinsertion and advancement 616 of the delivery system 602. Handle 612 canbe configured to facilitate the exertion of pressure, by a physician,onto the pulse generator delivery system 602, to facilitate theadvancement and positioning of the delivery system 602 at the desiredlocation within the patient.

Pulse generator delivery system 602 can include a pulse generatorrelease device 618. The release device 618 can be configured tofacilitate disengagement of the pulse generator 102 from the deliverysystem 602. In some variations, release device 618 can include a plunger620. Plunger 620 can include a distal end configured to engage with theproximal end 606 of the pulse generator delivery system 602. The plunger620 can engage with the proximal end 606 of the pulse generator deliverysystem 602 when the pulse generator 102 is loaded into the receptacle610 of the delivery system 602. The proximal end 622 of the plunger 620can extend from the proximal end 606 of the delivery system 602.

Plunger 620 can include a force applicator 624. Force applicator 624 canbe positioned at the proximal end 622 of plunger 620. Force applicator624 can be configured to facilitate application of a force to theplunger 620 to advance the plunger 620. Advancing plunger 620 can forcepulse generator 102 from the delivery system 602. In some variations,the force applicator 624 can be a ring member. The ring member canfacilitate insertion, by the physician, of a finger. Pressure can beapplied to the plunger 620 through the ring member, forcing the pulsegenerator 102 out of the receptacle 610 of the delivery system 602 intothe patient at its desired location. In some variations, the proximalend 622 of the plunger 620 can include a flat area, for example, similarto the flat area of a syringe, that allows the physician to applypressure to the plunger 620. In some variations, the plunger 620 can beactivated by a mechanical means such as a ratcheting mechanism.

The distal end 608 of the pulse generator delivery device 602 caninclude one or more sensors. The sensor(s) can be configured tofacilitate detection of a state of patient tissues adjacent distal end608 of the pulse generator delivery device 602. Various patient tissuescan emit, conduct and/or reflect signals. The emitted, conducted and/orreflected signals can provide an indication of the type of tissueencountered by the distal end 608 of the pulse generator delivery device602. Such sensor(s) can be configured, for example, to detect theelectrical impedance of the tissue adjacent the distal end 608 of thepulse generator delivery device 602. Different tissues can havedifferent levels of electrical impedance. Monitoring the electricalimpedance can facilitate a determination of the location, or tissueplane, of the distal end 608 of the delivery device 602.

In addition to delivery of the pulse generator, delivery of at least onelead for sensing and/or transmitting therapeutic electrical pulses fromthe pulse generator is typically required. Proper positioning of thedistal end of such lead(s) relative to the heart is very important.Delivery systems are provided that can facilitate the insertion of oneor more leads to the correct location(s) in the patient. The deliverysystems can facilitate finding the location of the initial insertionpoint for the lead. The initial insertion point optionally being anintercostal space associated with a patient's cardiac notch of the leftlung. The intercostal spaces associated with the cardiac notch commonlyinclude the left-hand-side fourth, fifth and sixth intercostal spaces.Other intercostal spaces on either side of the sternum may be used,especially when the patient is experiencing conditions that prevent useof the fourth, fifth and sixth intercostal spaces, or due to anatomicalvariations.

When making the initial insertion through the epidermis and theintercostal muscles of the patient, it is important to avoid damagingimportant blood-filled structures of the patient. Various techniques canbe employed to avoid damaging important blood-filled structures. Forexample, sensors can be used to determine the location of theblood-filled structures. Such sensors may include accelerometersconfigured to monitor pressure waves caused by blood flowing through theblood-filed structures. Sensors configured to emit and detectlight-waves may be used to facilitate locating tissues that absorbcertain wavelengths of light and thereby locate different types oftissue. Temperature sensors may be configured to detect differences intemperature between blood-filled structures and surrounding tissue.Lasers and detectors may be employed to scan laser light across thesurface of a patient to determine the location of subcutaneousblood-filled structures.

Conventional medical devices may be employed to locate the desiredinitial insertion point into the patient. For example, x-ray machines,MRI machines, CT scanning machines, fluoroscopes, ultrasound machinesand the like, may be used to facilitate determination of the initialinsertion point for the leads as well as facilitate in advancing thelead into the patient.

Advancing a lead into a patient can also present the risk of damagingphysiological structures of the patient. Sensors may be employed tomonitor the characteristics of tissues within the vicinity of the distalend of an advancing lead. Readings from sensors associated with thecharacteristics of tissues can be compared against known characteristicsto determine the type of tissue in the vicinity of the distal end of theadvancing lead.

Sensors, such as pH sensors, thermocouples, accelerometers, electricalimpedance monitors, and the like, may be used to detect the depth of thedistal end of the electrode in the patient. Physiologicalcharacteristics of the body change the further a lead ventures into it.Measurements performed by sensors at, or near, the distal end of theadvancing lead may facilitate the determination of the type of tissue inthe vicinity of the distal end of the lead, as well as its depth intothe patient.

Various medical imaging procedures, may be used on a patient todetermine the location of the desired positions in the heart for thedistal end of the lead(s). This information can be used, in conjunctionwith sensor readings, of the kind described herein, to determine whenthe distal end of the lead has advanced to a desired location within thepatient.

Components may be used to first create a channel to the desired locationfor the distal end of the lead. Components can include sheathes,needles, cannulas, balloon catheters and the like. A component may beadvanced into the patient with the assistance of sensor measurements todetermine the location of the distal end of the component. Once thecomponent has reached the desired location, the component may bereplaced with the lead or the lead may be inserted within the component.An example of a component can include an expandable sheath. Once thesheath has been advanced to the desired location, a cannula extendingthe length of the sheath may be expanded, allowing a lead to be passthrough the cannula. The sheath may then be removed from around thelead, leaving the lead in situ with the distal end of the lead at thedesired location.

Determination of the final placement of the distal end of a lead isimportant for the delivery of effective therapeutic electrical pulsesfor pacing the heart. The present disclosure describes multipletechnologies to assist in placement of a lead in the desired location.For example, the use of sensors on the pulse generator, on the distalend of leads, or on delivery components. In addition, when a lead orcomponent is advanced into a patient, balloons may be employed to avoiddamaging physiological structures of the patient. Inflatable balloonsmay be disposed on the distal end of the lead or component, on the sidesof a lead body of the lead, or may be circumferentially disposed aboutthe lead body. The balloons may be inflated to facilitate thedisplacement of tissue from the lead to avoid causing damage to thetissue by the advancing lead. A lead delivery assembly may also be usedto facilitate delivery of the lead to the desired location. In somevariations, the lead delivery assembly may be configured toautomatically deliver the distal end of the lead to the desired locationin the patient. Such a lead delivery system is disclosed in co-ownedU.S. patent application Ser. No. 14/846,578, filed Sep. 4, 2015, thedisclosure of which is incorporated herein by reference.

FIG. 7 is an illustration 700 of an exemplary process flow illustratinga method of delivering a lead having features consistent with thepresent disclosure. At 702, the location of blood-filled structures, inthe vicinity of an intercostal space, can be determined. The intercostalspace can be an intercostal space associated with the cardiac notch ofthe patient. Determining the location of the blood-filed structures maybe facilitated by one or more sensors configured to detect the locationof blood-filled structures.

At 704, a region can be chosen for advancing of a lead throughintercostal muscles associated with the cardiac notch. The region chosenmay be based on the determined location of blood-filled structures ofthe patient in that region. It is important that damage to blood-filledstructures, such as arteries, veins, and the like, is avoided whenadvancing a lead into a patient.

At 706, a lead can be advanced through the intercostal musclesassociated with the cardiac notch of the patient. Care should be takento avoid damaging important physiological structures. Sensors, of thekind described herein, may be used to help avoid damage to importantphysiological structures.

At 708, advancement of the lead through the intercostal muscles can beceased. Advancement may be ceased in response to an indication that thedistal end of the lead has advanced to the desired location. Indicationthat the distal end of the lead is at the desired location may beprovided through measurements obtained by one or more sensors of thekind described herein.

The lead advanced through the intercostal muscles associated with thecardiac notch of the patient can be configured to transmit therapeuticelectrical pulses to pace the patient's heart. FIG. 8A is anillustration 800 a of an exemplary lead 802 having features consistentwith the present disclosure. For the lead to deliver therapeuticelectrical pulses to the heart for pacing the heart, a proximal end 804of lead 802 is configured to couple with the pulse generator 102. Theproximal end 804 of lead 802 may be configured to couple with aconnection port 124. The connection port can be configured to couple theproximal end 804 of lead 802 to one or more conductors, such asconductors 118 and 120. When the proximal end 804 of lead 802 coupleswith connection port 124, a sealed housing may be formed between them.In some variations, the materials of connection port 124 and theproximal end 804 of lead 802 may be fused together. In some variations,the proximal end 804 of lead 802 may be configured to be pushed into thesealed housing 126, or vice versa. Optionally, the external diameter ofthe inserted member may be slightly greater than the internal diameterof the receiving member causing a snug, sealed fit between the twomembers. Optionally, a mechanism, such as a set-screw or mechanicallock, may be implemented upon the connection port 124 or proximal leadend 804 in order to prevent unintentional disconnection of the lead 802from pulse generator 102.

Also shown in FIG. 8A is the distal end 806 of lead 802. The distal end806 of lead 802 may comprise an electrode 808. In some variations, lead802 may include a plurality of electrodes. In such variations, lead 802may include a multiple-pole lead. Individual poles of the multiple-polelead can feed into separate electrodes. Electrode 808 at the distal end806 of lead 802 may be configured to deliver electrical pulses to pacethe heart when located in the desired position for pacing the heart.

The distal end 806 of lead 802 can include one or more sensors 810.Sensor(s) 810 can be configured to monitor physiological characteristicsof the patient while the distal end 806 of lead 802 is being advancedinto the patient. Sensors can be disposed along the length of lead 802.For example, sensor 812 is disposed some distance from the distal end806. Such sensors incorporated onto the lead can detect subtlephysiological, chemical and electrical differences that distinguish thelead's placement within the desired location, as opposed to otherlocations in the patient's thoracic cavity.

In some variations, the proximal end 804 of lead 802 may be coupled withpulse generator 102 prior to the distal end 806 of lead 802 beingadvanced through the intercostal space of the patient. In somevariations, the proximal end 804 of the lead 802 may be coupled withpulse generator 102 after the distal end 806 of lead 802 has beenadvanced to the desired location.

To assist in the placement of the lead, various medical instruments maybe used. The medical instruments may be used alone, or in combinationwith sensors disposed on the lead that is being placed. Medicalinstruments may be used to help the physician to access the desiredlocation for the placement of a lead and/or confirm that the distal endof the lead has reached the desired location. For example, instruments,such as an endoscope or laparoscopic camera, with its long, thin,flexible (or rigid) tube, light and video camera can assist thephysician in confirming that the distal end 806 of lead 802 has reachedthe desired location within the thoracic cavity. Other tools known toone skilled in the art such as a guidewire, guide catheter, or sheathmay be used in conjunction with medical instruments, such as thelaparoscopic camera, and may be advanced alongside and to the locationidentified by the medical instruments. Medical instruments such as aguidewire can be advanced directly to the desired location for thedistal end of the lead with the assistance of acoustic sound,ultrasound, real-time spectroscopic analysis of tissue, real-timedensity analysis of tissue or by delivery of contrast media that may beobserved by real-time imaging equipment.

In some variations, the patient may have medical devices previouslyimplanted that may include sensors configured to monitor physiologicalcharacteristics of the patient. The physiological characteristics of thepatient may change based on the advancement of the lead through theintercostal space of the patient. The previously implanted medicaldevice may have sensors configured to detect movement of the advancinglead. The previously implanted medical device can be configured tocommunicate this information back to the physician to verify thelocation of the advancing lead.

Sensors disposed on the lead, such as sensors 810 disposed on distal end806 of the lead may be used to facilitate the delivery of the lead tothe desired location. Sensor(s) 810 can be configured to facilitatedetermination of a depth of the distal end 806 of lead 802. As describedabove, the depth of the desired location within the patient can bedetermined using one or more medical instruments. This can be determinedduring implantation of the lead 802 or prior to the procedure takingplace.

Although sensor(s) 810 is illustrated as a single element in FIG. 8A,sensor(s) 810 can include multiple separate sensors. The sensors 810 canbe configured to facilitate placement of the distal end 806 of the lead802 at a desired location and verification thereof.

Sensor(s) 810 can be configured to transmit sensor information duringadvancement to the desired location. Sensor(s) 810 may transmit signalsassociated with the monitored physiological characteristics of thetissue within the vicinity of the distal end 806 of the lead 802. Insome variations, the signals from sensor(s) 810 may be transmitted to acomputing device(s) configured to facilitate placement of the lead 802in the desired location. In such variations, the computing device(s) canbe configured to assess the sensor information individually, or in theaggregate, to determine the location of the distal end 806 of lead 802.The computing device(s) can be configured to present alerts and/orinstructions associated with the position of the distal end 806 of lead802.

In some variations, lead 802 can be first coupled with connection port124 of pulse generator 102. Signals generated by sensor(s) 810 can betransmitted to a computing device(s) using transceiver 316 in pulsegenerator 102, as illustrated in FIG. 3.

An accelerometer may be used to facilitate delivery of the distal end806 of lead 802 to the desired location. An accelerometer may bedisposed at the distal end 806 of lead 802. The accelerometer may beconfigured to monitor the movement of the distal end 806 of lead 802.The accelerometer may transmit this information to a computing device orthe physician. The computing device, or the physician, can determine thelocation of the distal end 806 of the lead 802 based on the continuousmovement information received from the accelerometer as the lead 802 isadvanced into the patient. The computing device or the physician mayknow the initial entry position for lead 802. The movement informationcan indicate a continuous path taken by the lead 802 as it advanced intothe body of the patient, thereby providing an indication of the locationof the distal end 806 of lead 802. Pressure waves from the beating heartmay differ as absorption changes within deepening tissue planes. Thesepressure wave differences may be used to assess the depth of the distalend of the electrode.

The accelerometer can also be configured to monitor acoustic pressurewaves generated by various anatomical structures of the body. Forexample, the accelerometer can be configured to detect acoustic pressurewaves generated by the heart or by other anatomical structures of thebody. The closer the accelerometer gets to the heart, the greater theacoustic pressure waves generated by the heart will become. By comparingthe detected acoustical pressure waves with known models, a location ofthe distal end 806 of lead 802 can be determined.

Pressure waves or vibrations can be artificially generated to cause thepressure waves or vibrations to traverse through the patient. Thepressure waves or vibrations can be generated in a controlled manner.The pressure waves or vibrations may be distorted as they traversethrough the patient. The level of type of distortion that is likely tobe experienced by the pressure waves or vibrations may be known. Thepressure waves or vibrations detected by the accelerometer can becompared to the known models to facilitate determination or verificationof the location of the distal end 806 of lead 802.

Different tissues within a body exhibit different physiologicalcharacteristics. The same tissues situated at different locations withinthe body can also exhibit different physiological characteristics.Sensors, disposed on the distal end 806, of lead 802 can be used tomonitor the change in the physiological characteristics as the distalend 806 is advanced into the body of the patient. For example, thetissues of a patient through which a lead is advanced can demonstratediffering resistances, physiological properties, electrical impedance,temperature, pH levels, pressures, and the like. These differentphysiological characteristics, and the change in physiologicalcharacteristics, experienced as a sensor traverses through a body can beknown or identified. For example, even if the actual degree is not knownahead of time, the change in sensor input when the sensor traverses fromone tissue media to another may be identifiable in real-time.Consequently, sensors configured to detect physiological characteristicsof a patient can be employed to facilitate determining and verifying thelocation of the distal end 806 of lead 802.

Different tissues can exhibit different insulative properties. Theinsulative properties of tissues, or the change in insulative propertiesof tissues, between the desired entry-point for the lead and the desireddestination for the lead can be known. Sensor 810 can include anelectrical impedance detector. An electrical impedance detector can beconfigured to monitor the electrical impedance of the tissue in thevicinity of the distal end 806 of lead 802. The electrical impedance ofthe tissue monitored by the electrical impedance detector can becompared with the known insulative properties of the tissues between theentry point and the destination, to determine the location of the distalend of lead 802 or a transition from one tissue plane to another may berecognized by a measurable change in the measured impedance.

Varying levels of electrical activity can be experienced at differentlocations with the body. Electrical signals emitted from the heart, orother muscles can send electrical energy through the body. Thiselectrical energy will dissipate the further it gets from its source.Various tissues will distort the electrical energy in different ways.Sensors configured to detect the electrical energy generated by theheart and/or other anatomical structures can monitor the electricalenergy as the lead is advanced. By comparing the monitored electricalenergy with known models, a determination or verification of thelocation of the distal end 806 of lead 802 can be made. The sensors maybe configured to identify sudden changes in the electrical activitycaused by advancement of the sensor into different tissue planes.

Tissues throughout the body have varying pH levels. The pH levels oftissues can change with depth into the body. Sensor(s) 810 can include apH meter configured to detect the pH levels of the tissue in thevicinity of the sensor(s) 810 as the sensor(s) advance through thepatient. The detected pH levels, or detected changes in pH levels, canbe compared with known models to facilitate determination orverification of the location of the distal end 806 of lead 802. The pHmeter may be configured to identify sudden changes in the pH levelcaused by advancement of the meter into different tissue planes.

Different tissues can affect vibration-waves or sound-waves in differentways. Sensor(s) 810 can include acoustic sensors. The acoustic sensorscan be configured to detect vibration waves or sound waves travellingthrough tissues surrounding sensor(s) 810. The vibration waves can beemitted by vibration-emitting devices embedded the lead 802. Thevibration waves can be emitted by vibration-emitting devices located ona hospital gurney, positioned on the patient, or otherwise remote fromlead 802. Sensor(s) 810 can be configured to transmit detectedvibration-wave information to a computing device configured to determinethe location of the distal end 806 of lead 802 based on the detectedvibration-wave information.

Different tissues can have different known effects on the emittedelectromagnetic waves. Sensors can be used to detect the effect that thetissue in the vicinity of the sensors have on the electromagnet waves.By comparing the effect that the tissue has on the electromagnetic waveswith known electromagnetic effects, the identity of the tissue can beobtained and the location of the lead can be determined or verified. Forexample, sensor(s) 810 can include electromagnetic wave sensors.Electromagnetic wave sensors can include an electromagnetic wave emitterand an electromagnetic wave detector. The electromagnetic waves will beabsorbed, reflected, deflected, and/or otherwise affected by tissuesurrounding sensor(s) 810. Sensor(s) 810 can be configured to detect thechange in the reflected electromagnetic waves compared to the emittedelectromagnetic waves. By comparing the effect the tissue in thevicinity of the sensor(s) 810 has on the electromagnetic waves withknown models, a determination verification of the location of lead 802can be made. The sensors may be configured to identify sudden changes inthe electromagnetic activity caused by advancement of the sensor intodifferent tissue planes.

FIG. 9A is an illustration 900 of the distal end of an exemplarydelivery system 902 having features consistent with the presentlydescribed subject matter. While FIG. 9A is described with reference to adelivery system, one of ordinary skill in the art can appreciate andunderstand that the technology described herein could be applieddirectly to the end of a lead, such as lead 802. The present disclosureis intended to apply to a delivery system, such as delivery system 902,as well as a lead, such as lead 802.

Delivery system 902 can facilitate placement of the distal end of alead, such as lead 802 illustrated in FIG. 8, to a desired location byuse of electromagnetic waves, such as light waves. Delivery system 902may comprise a delivery catheter body 904. Delivery catheter body 904may be configured to facilitate advancement of delivery catheter body904 into the patient to a desired location. The distal tip 906 ofdelivery catheter body 904 may comprise a light source 908. Light source908 can be configured to emit photons having a visible wavelength,infrared wavelength, ultraviolet wavelength, and the like. Deliverycatheter body 904 may comprise a light detector 910. Light detector 910may be configured to detect light waves, emitted by the light source908, reflected by tissues surrounding distal tip 906 of deliverycatheter body 904.

FIG. 9B is an illustration 912 of an exemplary process for using thedelivery system illustrated in FIG. 9A. Light detector 910 can beconfigured to detect light waves reflected by the tissue adjacent thedistal end 906 of delivery system 902. Information associated with thedetected light waves may be transmitted to a computing device. Thecomputing device can be configured to interpret the informationtransmitted from light detector 910 and determine a difference betweenthe light emitted and the light detected.

At 914, light source 908 can be activated. Light source 908 may emitlight-waves into the tissue in the general direction of the intendedadvancement of delivery system 902. At 916, the tissue can absorb aportion of the emitted light waves. At 918, light detector 910 candetect the reflected light waves, reflected by tissues surrounding lightsource 908. At 920, a determination of a change in the absorption of thelight waves by tissues surrounding the distal tip 906 of delivery system902 can be made.

At 922, in response to an indication that the absorption of light waveshas not changed, delivery system 902 can be configured to advance adelivery system, such as delivery system 902, into the patient. In somevariations, a physician can advance delivery system 902 into thepatient. In other variations, the delivery system 902 can be advancedinto the patient automatically.

At 924, in response to an indication that the absorption of light waveshas changed, an alert can be provided to the physician. In somevariations, the alert can be provided to the physician through acomputing device configured to facilitate positioning of delivery system902 into the patient.

In some variations, a computing device may be configured to facilitatepositioning of delivery system 902 into the patient. The computingdevice can be configured to alert the physician to the type of tissue inthe vicinity of distal tip 906 of delivery system 902. In somevariations, the computing device can be configured to alert thephysician when the distal tip 906 reaches a tissue havingcharacteristics consistent with the desired location of the distal tip906 of delivery system 902. For example, when the characteristics of thetissue in the vicinity of the distal tip 906 match those within theintercostal tissues, or a particular location within the medistiunum, analert may be provided.

Blood vessels, both venous and arterial, absorb red, near infrared andinfrared (IR) light waves to a greater degree than surrounding tissues.When illuminating the surface of the body with red, near infrared andinfrared (IR) light waves, blood rich tissues, for example veins, willabsorb more of this light than other tissues, and other tissues willreflect more of this light than the blood rich tissues. Analysis of thepattern of reflections can enable the blood rich tissues to be located.A positive or negative image can be projected on the skin of the patientat the location of the vein. In some variations, the vein can berepresented by a bright area and the absence of a vein can berepresented as a dark area, or vice versa.

Delivery system 902 can include a subcutaneous visualization enhancer.The subcutaneous visualization enhancer may be configured to enhancevisualization of veins, arteries, and other subcutaneous structures ofthe body. The subcutaneous visualization enhancer can include movinglaser light sources to detect the presence of blood-filled structures,such as venous or arterial structures below the surface of the skin. Thesubcutaneous visualization enhancer can include systems configured toproject an image onto the surface of the skin that can show an operatorthe pattern of the detected subcutaneous blood-filled structures. Laserlight from laser light sources can be scanned over the surface of thebody using mirrors. A light detector can be configured to measure thereflections of the laser light and use the pattern of reflections toidentify the targeted blood rich structures.

Such subcutaneous visualization enhancers can be used to facilitatedetermination of the location for the initial approach for inserting alead, such as lead 802, through the intercostal space associated withthe cardiac notch of the patient. In some variations, the visualizationenhancers can be disposed remote from the delivery system and/or can beconfigured to enhance visualization enhancers disposed on the deliverysystem.

With the provision of a visualization of the detected subcutaneousstructures, the physician can assess the position of subcutaneousstructures such as the internal thoracic artery, or other structures, ofthe body while concurrently inserting components of the delivery systeminto the body, while avoiding those subcutaneous structures.

In some variations, during advancement of lead 802 through theintercostal space associated with the cardiac notch, sensor(s) 810 canbe configured to transmit obtained readings to a computing device forinterpretation. In some variations, the computing device is pulsegenerator 102. In some variations, pulse generator 102 is used totransmit the readings to an external computing device forinterpretation. In any event, the sensor information from the varioussensors can be used individually, or accumulatively, to determine thelocation of the distal end of lead 802.

FIG. 10 is a schematic illustration of a delivery control system 1000having features consistent with the current subject matter. The deliverycontrol system 1000 can be configured to automatically deliver a lead tothe desired position within the patient. For example, the deliverycontrol system 1000 can be configured to automatically deliver a distaltip of a lead through the intercostal space associated with the cardiacnotch.

Delivery control system 1000 can be configured to receive a plurality ofinputs. The inputs can come from one or more sensors disposed in, or on,the patient. For example, delivery control system 1000 can be configuredto receive subcutaneous structure visualization information 1002,information associated with delivery insertion systems 1004, informationassociated with sensors 1006, and the like.

Delivery control system 1000 can be configured to use remote sensors1006 to facilitate determination of the insertion site for the lead.Sensors 1006 can be disposed in various instruments configured to beinserted into the patient. Sensors 1006 can also be disposed in variousinstruments configured to remain external to the patient.

Delivery control system 1000 can be configured to perform depthassessments 1008. The depth assessments 1008 can be configured todetermine the depth of the distal end of an inserted instrument, such asa lead 802 illustrated in FIG. 8A. Depth assessments 1008 can beconfigured to determine the depth of the distal end of the insertedinstrument through light detection systems 1010, pressure wave analysis1012, acoustic analysis, and the like.

Depth assessments 1008 can be configured to determine the depth of thedelivery system, or lead, though pressure wave analysis systems 1012.Pressure waves can be detected by accelerometers as herein described.

Depth assessments 1008 can be configured to determine the depth of thedelivery system though acoustic analysis systems 1014. Acoustic analysissystem 1014 can be configured to operate in a similar manner to astethoscope. The acoustic analysis system 1014 can be configured todetect the first heart sound (S1), the second heart sound (S2), or otherheart sounds. Based on the measurements obtained by the acousticanalysis system 1014, a depth and/or location of the distal end of adelivery system and/or inserted medical component can be determined. Theacoustic analysis system 1014 can be configured to measure the duration,pitch, shape, and tonal quality of the heart sounds. By comparing theduration, pitch, shape, and tonal quality of the heart sounds with knownmodels, a determination or verification of the location of the lead canbe made. Sudden changes in the degree of heart sounds may be used toindicate advancement into a new tissue plane.

In some variations, the lead can include markers or sensors thatfacilitate the correct placement of the lead. Certain markers such as avisual scale, radiopaque, magnetic, ultrasound markers, and the like,can be position at defined areas along the length of the lead so thatthe markers can be readily observed by an implanting physician, orautomated system, on complementary imaging instruments such asfluoroscopy, x-ray, ultrasound, or other imaging instruments known inthe art. Through the use of these markers, the physician, or automatedimplantation device, can guide the lead to the desired location withinthe intercostal muscle, pleural space, mediastinum, or other desiredposition, as applicable.

Avoiding damage to tissues in the vicinity of the path-of-travel for thelead is important. Moving various tissues from the path of the leadwithout damaging them is also important. FIGS. 11A and 11B areillustrations 1100 and 1102 of an exemplary lead 802 having featuresconsistent with the present disclosure for moving and avoiding damage totissues during lead delivery. Lead 802 can comprise a distal tip 1104.Distal tip 1104 can include at least one electrode and/or sensor 1106.

Having leads directly touch the tissue of a patient can be undesirableand can damage the tissue. Consequently, the distal tip 1106 of lead 802can include an inflatable balloon 1108. Balloon 1108 can be inflatedwhen the distal tip 1106 of lead 802 encounters an anatomical structureobstructing its path, or prior to moving near sensitive anatomy duringlead delivery. The balloon may be configured to divert the obstacleand/or the lead to facilitate circumventing the anatomical structure ormay indicate that the lead has reached its intended destination.

To inflate the balloon, lead 802 can include a gas channel 1110. At theend of gas channel 1110 there can be a valve 1112. Valve 1112 can becontrolled through physical manipulation of a valve actuator, throughelectrical stimulation, through pressure changes in gas channel 1110and/or controlled in other ways. In some variations, the valve 1112 maybe configured at the proximal end of the lead 802.

When positioning lead 802 into a patient, lead 802 may cause damage to,or perforations of, the soft tissues of the patient. When lead 802 isbeing installed into a patient, distal tip 1104 of lead 802 canencounter soft tissue of the patient that should be avoided. In responseto encountering the soft tissue of the patient, gas can be introducedinto gas channel 1110, valve 1112 can be opened and balloon 1108 can beinflated, as shown in FIG. 11B. Inflating balloon 1108 can cause theballoon to stretch and push into the soft tissue of the patient, movingthe soft tissue out of the way and/or guiding distal tip 1104 of lead802 around the soft tissue. When distal tip 1104 of lead 802 has passedby the soft tissue obstruction, valve 1112 can be closed and the balloondeflated.

In some variations, a delivery component or system is used to facilitatedelivery of a lead, such as lead 802, to the desired location. FIG. 12is an illustration 1200 of an exemplary delivery system for a leadhaving features consistent with the present disclosure. An example ofthe delivery system is an expandable sheath 1202. Expandable sheath 1202can be inserted into the patient at the desired insertion point,identified using one or more of the technologies described herein.Expandable sheath 1202 can include a tip 1204. In some variations, tip1204 may be radiopaque. A radiopaque tip 1204 may be configured tofacilitate feeding of the expandable sheath 1202 to a desired locationusing one or more radiography techniques known in the art and describedherein. Such radiography techniques can include fluoroscopy, CT scan,and the like.

Tip 1204 can include one or more sensors for facilitating the placementof the lead. The sensors included in tip 1204 of the expandable sheath1202 can be the same or similar to the sensors described herein formonitoring physiological characteristics of the body and othercharacteristics for facilitating positioning of a lead in a body.

Expandable sheath 1202 can include a channel 1206 running through ahollow cylinder 1208 of expandable sheath 1202. When tip 1204 ofexpandable sheath 1202 is at the desired location, gas or liquid can beintroduced into hollow cylinder 1208. The gas or liquid can beintroduced into hollow cylinder 1208 through a first port 1210. Hollowcylinder 1208 can expand, under the pressure of the gas or liquid,causing channel 1206 running through hollow cylinder 1208 to increase insize. A lead, such as lead 802 illustrated in FIG. 8A, can be insertedinto channel 1206 through a central port 1212. Hollow cylinder 1208 canbe expanded until channel 1206 is larger than the lead. In somevariations, channel 1206 can be expanded to accommodate leads of severalFrench sizes. Once the lead is in the desired place, expandable sheath1202 can be removed, by allowing the lead to pass through channel 1206.In some variations, liquid or gas can be introduced into or removed fromchannel 1006 through a second port 1214.

Using expandable sheath 1202 can provide an insertion diameter smallerthan the useable diameter. This can facilitate a reduction in the riskof damage to tissues and vessels within the patient when placing thelead.

When electricity is brought within the vicinity of muscle tissue, themuscle will contract. Consequently, having a lead for carryingelectrical pulses traversing through intercostal muscle tissue may causethe intercostal muscle tissue to contract. Electrical insulation can beprovided in the form of a receptacle disposed in the intercostal muscle,where the receptacle is configured to electrically insulate theintercostal muscle from the lead.

FIG. 13 is an illustration 1300 of an intercostal space 1302 associatedwith the cardiac notch of the left lung with an exemplary leadreceptacle 1304 having features consistent with the present disclosure.Lead receptacle 1304 can facilitate the placement of leads, and/or otherinstruments and avoid the leads and/or instruments physically contactingthe intercostal tissue. When the distal end of the lead is positioned toterminate in the intercostal muscle, the lead can be passed through leadreceptacle 1304 that has been previously placed within the patient'sintercostal muscles. Lead receptacle 1304 can be configured to beelectrically insulated so that electrical energy emanating from the leadwill not stimulate the surrounding intercostal and skeletal muscletissue, but will allow the electrical energy to traverse through andstimulate cardiac tissue.

The intercostal space 1302 is the space between two ribs, for example,rib 1306 a and rib 1306 b. Intercostal muscles 1308 a, 1308 b and 1308 ccan extend between two ribs 1306 a and 1306 b, filling intercostal space1302. Various blood vessels and nerves can run between the differentlayers of intercostal muscles. For example, intercostal vein 1310,intercostal artery 1312, the intercostal nerve 1314 can be disposedunder a flange 1316 of upper rib 1306 a and between the innermostintercostal muscle 1308 c and its adjacent intercostal muscle 1308 b.Similarly, collateral branches 1318 can be disposed between theinnermost intercostal muscle 1308 c and its adjacent intercostal muscle1308 b.

The endothoracic facia 1320 can abut the inner-most intercostal muscle1308 c and separate the intercostal muscles from the parietal pleura1322. The pleural cavity 1324 can be disposed between the parital pleura1322 and the visceral pleura 1326. The visceral pleura 1326 can abut thelung 1328.

FIG. 14 is an illustration 1400 of an exemplary lead fixation receptacle1304 illustrated in FIG. 13, having features consistent with the presentdisclosure.

Lead receptacle 1304 may comprise a cylindrical body, or lumen 1328,from an outer side of an outermost intercostal muscle to an inner sideof an innermost intercostal muscle of an intercostal space. Lumen 1328may be configured to support a lead traversing through it. Lumen 1328may comprise an electrically insulating material configured to inhibittraversal of electrical signals through walls of lumen 1328. In somevariations, end 1336 of the receptacle 1304 may pass through theinnermost intercostal muscle 1308 c. In some variations, end 1338 ofreceptacle 1304 can pass through outermost intercostal muscle 1308 a.

Lumen 1328 can terminate adjacent the pleural space 1324. In somevariations, the lumen 1328 can terminate in the mediastinum. In somevariations, receptacle 1304 can be configured to be screwed into theintercostal muscles 1308 a, 1308 b, and 1308 c. Receptacle 1304 can alsobe configured to be pushed into the intercostal muscles 1308 a, 1308 band 1308 c.

Lead receptacle 1304 may include a fixation flange 1330 a. Fixationflange 1330 a may be disposed on the proximal end of the lumen 1328 andconfigured to abut the outermost intercostal muscle 1308 a. Leadreceptacle 1304 may include a fixation flange 1330 b. Fixation flange1330 b can be disposed on the distal end of the lumen 1328 andconfigured to abut the outermost intercostal muscle 1308 c. Leadreceptacle 1304 can be implanted into the intercostal muscles 1308 a,1308 b, and 1308 c by making an incision in the intercostal muscles 1308a, 1308 b, and 1308 c, stretching the opening and positioning leadreceptacle 1304 into the incision, taking care to ensure that theincision remains smaller than the outer diameter of flanges 1330 a and1330 b. In some variations flanges 1330 a and 1330 b can be configuredto be retractable allowing for removal and replacement of the leadfixation receptacle 1304.

Lead receptacle 1304 can be fixed in place by using just flanges 1330 aand 1330 b. Lead receptacle 1304 may also be fixed in place by using aplurality of surgical thread eyelets 1332. Surgical thread eyelets 1332can be configured to facilitate stitching lead receptacle 1304 to theintercostal muscles 1308 a and 1308 c to fix lead receptacle 1304 inplace.

Receptacle 1304 can include an internal passage 1334. Internal passage1334 can be configured to receive one or more leads and facilitate theirtraversal through the intercostal space 1302.

Lead receptacle 1304 can be formed from an electrically insulatingmaterial. The electrically insulating material can electrically isolatethe intercostal muscles 1308 a, 1308 b and 1308 c from the leadstraversing through lead receptacle 1304.

Lead receptacle 1304 can be formed from materials that are insulative.The material can include certain pharmacological agents. For example,antibiotic agents, immunosuppressive agents to avoid rejection of leadreceptacle 1304 after implantation, and the like. In some variations,lead receptacle 1304 can be comprised of an insulative polymer coated orinfused with an analgesic. In some variations, the lead receptacle 1304can be comprised of an insulative polymer coated or infused with ananti-inflammatory agent. The polymer can be coated or infused with otherpharmacological agents known to one skilled in the art to treat acuteadverse effects from the implantation procedure or chronic adverseeffects from the chronic implantation of the lead or receptacle withinthe thoracic cavity.

FIG. 15 is an illustration of lead receptacle 1304 having featuresconsistent with the present disclosure. Lead fixation receptacle cancomprise a septum 1340, or multiple septums disposed traversely withinlumen 1338. Septum 1340 can be selectively permeable such that when alead is inserted through septum 1340, septum 1340 can be configured toform a seal around the lead traversing through lumen 1338 to prevent theingress or egress of gas, fluid, other materials, and the like, throughlumen 1338. Septum 1340 may optionally permit the egress of certain gasand fluid but prevent ingress of such materials through lumen 1338.

In some variations, the lead receptacle can comprise multiple lumens.For example, lead receptacle can comprise a second lumen configured totraverse from an outermost side of an outermost intercostal muscle to aninnermost side of an innermost intercostal muscle. Second lumen can beconfigured to facilitate dispensing of pharmacological agents into thethorax of the patient.

The lumens for such a lead receptacle can be used for differing purposesin addition to the passage of a single lead into the pleural space ormediastinum. The multiple lumens can provide access for multiple leadsto be passed into the pleural space or mediastinum.

FIG. 16 is an illustration of an exemplary lead fixation receptacle 1342having features consistent with the present disclosure. Lead fixationreceptacle 1342 can include a first lumen 1344, similar to lumen 1338 ofthe lead receptacle 1304 illustrated in FIGS. 14 and 15. Lead fixationreceptacle 1342 can include an additional lumen 1346. Additional lumen1346 can be provided as a port to provide access to the thoracic cavityof the patient. Access can be provided to facilitate dispensing ofpharmacological agents, such as pharmacological agents to treat variousadverse effects such as infection or pain in the area surrounding leadreceptacle 1342, pleural space, mediastinum, and/or other areassurrounding the thoracic cavity of the patient. Additional lumen 1346can provide access for treatment of other diseases or disordersaffecting organs or other anatomical elements within the thoraciccavity. For example, additional lumen 1346 can facilitate the evacuationof gas or fluid from the thorax, and the like.

The lead receptacle as described with reference to FIGS. 13-16 can befixated to cartilage, or bone within the thoracic cavity. In somevariations, the lead receptacle can be configured to be disposed betweenthe intercostal muscles and a rib, thereby potentially reducing damageto the intercostal muscles caused by its insertion. The lead receptaclecan be in passive contact with tissue surrounding the cardiac notch. Forexample, the lead receptacle can abut the superficial facia on theoutermost side and the endothoracic facia or the parietal pleura on theinnermost side.

In some variations, the lead receptacle can be actively fixed intoposition using one end of the lead receptacle. For example, only oneflange can include surgical thread holes to facilitate sewing of theflange into the intercostal muscles.

Active fixation, whether at flanges, or along the lumen of the leadfixation receptacle, can include, for example, the use of tines, hooks,springs, screws, flared wings, flanges and the like. Screws can be usedto screw the lead fixation receptacle into bone or more solid tissueswithin the thoracic cavity. Hooks, tines, springs, and the like, can beused to fix the lead fixation receptacle into soft tissues within thethoracic cavity.

In some variations the lead receptacle can be configured to facilitatein-growth of tissue into the material of which the lead fixationreceptacle is comprised. For example, the lead fixation receptacle canbe configured such that bone, cartilage, intercostal muscle tissue, orthe like, can readily grow into pockets or fissures within the surfaceof the lead receptacle. Facilitating the growth of tissue into thematerial of the lead receptacle can facilitate fixation of thereceptacle.

In some variations, the receptacle can be configured to actively fixbetween layers of the intercostal muscle. With reference to FIG. 13, thelayered nature of the intercostal muscle layers 1308 a, 1308 b and 1308c can be used to facilitate fixation of the lead receptacle into theintercostal space. For example, flanges can be provided that extendbetween the intercostal muscle layers. Incisions can be made at off-setpositions at each layer of intercostal muscle such that when the leadreceptacle is inserted through the incisions, the intercostal musclesapply a transverse pressure to the lead receptacle keeping it in place.For example, a first incision can be made in the first intercostalmuscle layer 1308 a, a second incision can be made in the secondintercostal muscle layer 1308 b, offset from the first incision, and athird incision can be made to the third intercostal muscle layer 1308 cin-line with the first incision. Inserting the lead receptacle throughthe incisions, such that the lead receptacle is situated through allthree incisions, will cause the second intercostal muscle layer 1308 bto apply a transverse pressure to the lead receptacle that is counteredby the first intercostal muscle layer 1308 a and the third intercostalmuscle layer 1308 c, facilitating keeping the lead receptacle in place.

Sensing and detection will be performed using one or more availablesignals to determine when pacing should be delivered or inhibited.Cardiac signals will be measured from one or more electrodes. Additionalnon-cardiac sensors may also be used to enhance the accuracy of sensingand detection. Such sensors include, but are not limited to rateresponse sensors, posture/positional sensors, motion/vibration sensors,myopotential sensors and exogenous noise sensors. One or more algorithmswill be utilized to make decisions about pacing delivery and inhibition.Such algorithms will evaluate available signal attributes andrelationships, including but not limited to analysis of morphology,timing, signal combinations, signal correlation, template matching orpattern recognition.

A pulse generator, such as pulse generator 102 illustrated in FIG. 1,can be configured to monitor physiological characteristics and physicalmovements of the patient. Monitoring can be accomplished through sensorsdisposed on, or in, the pulse generator, and/or through sensors disposedon one or more leads disposed within the body of the patient. The pulsegenerator can be configured to monitor physiological characteristics andphysical movements of the patient to properly detect heart arrhythmias,dyssynchrony, and the like.

Sensor(s) can be configured to detect an activity of the patient. Suchactivity sensors can be contained within or on the housing of the pulsegenerator, such as pulse generator 102 illustrated in FIG. 1. Activitysensors can comprise one or more accelerometers, gyroscopes, positionsensors, and/or other sensors, such as location-based technology, andthe like. Sensor information measured by the activity sensors can becross-checked with activity information measured by any concomitantdevices.

In some variations, an activity sensor can include an accelerometer. Theaccelerometer can be configured to detect accelerations in any directionin space. Acceleration information can be used to identify potentialnoise in signals detected by other sensor(s), such as sensor(s)configured to monitor the physiological characteristics of the patient,and the like, and/or confirm the detection of signals indicatingphysiological issues, such as arrhythmias or other patient conditions.

In some variations, a lead, such as lead 802 in FIG. 8, can beconfigured to include sensors that are purposed solely for monitoringthe patient's activity. Such sensors may not be configured to provideadditional assistance during the implantation procedure. These sensorscan include pulmonary, respiratory, minute ventilation, accelerometer,hemodynamic, and/or other sensors. Those sensors known in the art thatare used to real-time, or periodically monitor a patient's cardiacactivity can be provided in the leads. These sensors are purposed toallow the implanted device to sense, record and in certain instances,communicate the sensed data from these sensors to the patient'sphysician. In alternative embodiments, the implanted medical device mayalter the programmed therapy regimen of the implanted medical devicebased upon the activity from the sensors.

In some variations, sensors, such as sensors 810 and 812 of FIG. 8A, maybe configured to detect the condition of various organs and/or systemsof the patient. Sensor(s) 810, 812 can be configured to detect movementof the patient to discount false readings from the various organs and/orsystems. Sensor(s) 810, 812 can be configured to monitor patientactivity. Having a distal end 806 of lead 802 positioned in the cardiacnotch abutting the parietal pleura, sensor(s) 810, 812 can collectinformation associated with the organs and/or systems of the patient inthat area, for example the lungs, the heart, esophagus, arteries, veinsand other organs and/or systems. Sensor(s) 810 can include sensors todetect cardiac ECG, pulmonary function, sensors to detect respiratoryfunction, sensors to determine minute ventilation, hemodynamic sensorsand/or other sensors. Sensors can be configured independently to monitorseveral organs or systems and/or configured to monitor severalcharacteristics of a single organ simultaneously. For example, using afirst sensor pair, the implanted cardiac pacing system may be configuredto monitor the cardiac ECG signal from the atria, while simultaneously,a second sensor pair is configured to monitor the cardiac ECG signalfrom the ventricles.

A lead disposed in the body of a patient, such as lead 802 of FIG. 8A,can include sensors at other areas along the lead, for example, sensors812. The location of sensors 812 along lead 802 can be chosen based onproximity to organs, systems, and/or other physiological elements of thepatient. The location of sensors 812 can be chosen based on proximity toother elements of the implanted cardiac pacing system.

Additional leads may be used to facilitate an increase in the sensingcapabilities of the implantable medical device. In one embodiment, inaddition to at least one lead disposed within the intercostal muscle,pleural space or mediastinum, another lead is positioned subcutaneouslyand electrically connected to the implantable medical device. Thesubcutaneously placed lead can be configured to enhance the implantablemedical device's ability to sense and analyze far-field signal's emittedby the patient's heart. In particular, the subcutaneous lead enhancesthe implantable medical device's ability to distinguish signals fromparticular chambers of the heart, and therefore, appropriatelycoordinate the timing of the required pacing therapy delivered by theimplantable medical device.

Additional leads in communication with the implantable medical device orpulse generator, and/or computing device, can be placed in other areaswithin the thoracic cavity in order to enhance the sensing activity ofthe heart, and to better coordinate the timing of the required pacingtherapy delivered by the implantable medical device. In certainembodiments, these additional leads are physically attached to theimplantable medical device of the present disclosure.

The leads used to deliver therapeutic electrical pulses to pace theheart can comprise multiple poles. Each pole of the lead can beconfigured to deliver therapeutic electrical pulses and/or obtainsensing information. The different leads can be configured to providedifferent therapies and/or obtain different sensing information. Havingmultiple sensors at multiple locations can increase the sensitivity andeffectiveness of the provided therapy.

FIG. 8B is an illustration 800 b of an exemplary lead 802 havingfeatures consistent with the present disclosure. In some variations,lead 802 can comprise a yoke 816. The yoke can be configured to maintaina hermetically sealed housing for the internal electrical cables of lead802, while facilitating splitting of the internal electrical cables intoseparate end-leads 818 a, 818 b, 818 c. Yoke 816 can be disposed towarddistal end of lead 802. While three end-leads 818 a, 818 b, 818 c areillustrated in FIG. 8B, the current disclosure contemplates fewerend-leads as well as a greater number of end-leads emanating from yoke816.

The different end-leads 818 a, 818 b, 818 c, can include differentelectrodes and/or sensors. For example, end-lead 818 b can include anelectrode 808 b at the distal end 806 b of end-lead 818 b that differsfrom electrode 808 a at distal end 806 a of end-lead 818 a. Electrode808 b can have flanges 820. Flanges 820 can be configured to act as ananchor, securing the distal end 806 b of end-lead 818 b in positionwithin the patient. Electrode 808 b with flanges 820 can be suitable foranchoring into high-motion areas of the body where end-lead 818 b wouldotherwise move away from the desired location without the anchoringeffect provided by flanges 820. Similarly, electrode 808 c at the distalend 806 c of end-lead 818 c can be configured for a different functioncompared to the electrodes at the end of other end-leads.

Lead 802 can be a multi-pole lead. Each pole can be electronicallyisolated from the other poles. The lead 802 can include multipleisolated poles, or electrodes, along its length. The individual polescan be selectively activated. The poles may include sensors formonitoring cardiac or other physiological conditions of the patient, orelectrodes for deliver therapy to the patient.

The sensing characteristics of a patient can change over time, or canchange based on a patient's posture, a multi-pole lead permits theimplantable medical device facilitate monitoring a patient's statethrough multiple sensing devices, without requiring intervention toreposition a lead. Furthermore, a multi-pole lead can be configured tofacilitate supplementary sensing and therapy delivery vectors, such assensing or stimulating from one pole to a plurality of poles, sensing orstimulating from a plurality of poles to a single pole, or sensing orstimulating between a plurality of poles to a separate plurality ofpoles. For example, should one particular vector be ineffective attreating a particular arrhythmia, the implantable medical device, orpulse generator, can be configured to switch vectors between the poleson the lead and reattempt therapy delivery using this alternativevector. This vector switching is applicable for sensing. Sensingcharacteristics can be monitored, and if a sensing vector becomesineffective at providing adequate sensing signals, the implantablemedical device can be configured to switch vectors or use a combinationof one or more sensor pairs to create a new sensing signal.

In some variations, at yoke 816, each of the poles of the multi-polelead can be split into their separate poles. Each of the end-leadsemanating from the yoke 816 can be associated with a different pole ofthe multi-pole lead.

Some of the end-leads emanating from yoke 816 can be configured forproviding sensor capabilities of and/or therapeutic capabilities to thepatient's heart. Others of the end-leads emanating from yoke 816 can beconfigured to provide sensor capabilities and/or therapeuticcapabilities that are unrelated to the heart. Similarly, the cardiacpacing system herein described can include leads 802, or medical leads,that provide functionality unrelated to the heart.

In some variations, the lead can be bifurcated. A bifurcated lead cancomprise two cores within the same lead. In some variations, thedifferent cores of the bifurcated lead can be biased to bend in apredetermined manner and direction upon reaching a cavity. Such a cavitycan, for example, be the mediastinum. Bifurcated lead cores can becomprised of shape memory materials, for example, nitinol or othermaterial known in the art to deflect in a predetermined manner uponcertain conditions. The conditions under which the bifurcated lead coreswill deflect include electrical stimulation, pressure, temperature, orother conditions. In some variations, each core of the bifurcated leadcan be configured so that it is steerable by the physician, or anautomated system, to facilitate independent advancement of each core ofthe bifurcated lead, in different directions.

In some variations, sensors from the cardiac pacing system may beselected to optimize sensing characteristics of the cardiac signals.Sensing signals, comprised from one or more sensor pairs may be selectedvia manual operation of the programming system or automatic operation ofthe implanted cardiac pacing system. Sensing signals may be evaluatedusing one of several characteristics including signal amplitude,frequency, width, morphology, signal-to-noise ratio, and the like.

The cardiac pacing system can be configured to use multiple sensors togenerate one or more input signals, optionally apply filtering ofvarying levels to these signals, perform some form of verification ofacceptance upon the signals, use the signals to measure levels ofintrinsic physiological activity to, subsequently, make therapy deliverydecisions. Methods to perform such activities in part or in totalinclude hardware, software, and/or firmware based signal filters, signalamplitude/width analysis, timing analysis, morphology analysis,morphological template comparison, signal-to-noise analysis, impedanceanalysis, acoustic wave and pressure analysis, or the like. Thedescribed analyses may be configured manually via the programming systemor via automatic processes contained with the operation software of thecardiac pacing system.

While components have been described herein in their individualcapacities, it will be readily appreciated the functionality ofindividually described components can be attributed to one or more othercomponents or can be split into separate components. This disclosure isnot intended to be limiting to the exact variations described herein,but is intended to encompass all implementations of the presentlydescribed subject matter.

In the descriptions above and in the claims, phrases such as “at leastone of” or “one or more of” may occur followed by a conjunctive list ofelements or features. The term “and/or” may also occur in a list of twoor more elements or features. Unless otherwise implicitly or explicitlycontradicted by the context in which it used, such a phrase is intendedto mean any of the listed elements or features individually or any ofthe recited elements or features in combination with any of the otherrecited elements or features. For example, the phrases “at least one ofA and B;” “one or more of A and B;” and “A and/or B” are each intendedto mean “A alone, B alone, or A and B together.” A similarinterpretation is also intended for lists including three or more items.For example, the phrases “at least one of A, B, and C;” “one or more ofA, B, and C;” and “A, B, and/or C” are each intended to mean “A alone, Balone, C alone, A and B together, A and C together, B and C together, orA and B and C together.” Use of the term “based on,” above and in theclaims is intended to mean, “based at least in part on,” such that anunrecited feature or element is also permissible.

The subject matter described herein can be embodied in systems,apparatus, methods, and/or articles depending on the desiredconfiguration. The implementations set forth in the foregoingdescription do not represent all implementations consistent with thesubject matter described herein. Instead, they are merely some examplesconsistent with aspects related to the described subject matter.Although a few variations have been described in detail above, othermodifications or additions are possible. In particular, further featuresand/or variations can be provided in addition to those set forth herein.For example, the implementations described above can be directed tovarious combinations and subcombinations of the disclosed featuresand/or combinations and subcombinations of several further featuresdisclosed above. In addition, the logic flows depicted in theaccompanying figures and/or described herein do not necessarily requirethe particular order shown, or sequential order, to achieve desirableresults. Other implementations may be within the scope of the followingclaims.

What is claimed is:
 1. A lead receptacle comprising: a lumen configuredto traverse from an outer side of an outermost intercostal muscle to aninner side of an innermost intercostal muscle of an intercostal space ofa patient and to support a lead traversing through the lumen, whereinthe lumen is configured to support one or more cardiac leads traversingthrough the intercostal space.
 2. The cardiac pacing system as in claim1, wherein the lumen comprises an electrically insulating materialconfigured to inhibit traversal of electrical signals through walls ofthe lumen.
 3. The lead receptacle of claim 1, wherein the intercostalspace of the patient is the intercostal space associated with a cardiacnotch of the left lung of the patient.
 4. The lead receptacle of claim1, wherein the proximal end of the lumen is configured to terminateadjacent the pleural space of the patient.
 5. The lead receptacle ofclaim 1, wherein the proximal end of the lumen is configured toterminate in the mediastinum of the patient.
 6. The lead receptacle ofclaim 1, wherein the one or more cardiac leads are configured to carryelectrical stimulation therapy from a pulse generator to a heart of thepatient.
 7. The lead receptacle of claim 1, wherein the one or morecardiac leads are configured to carry information from one or moresensors disposed in the one or more cardiac leads.
 8. The leadreceptacle of claim 1, further comprising at least one flange forengaging with an inner surface of an intercostal muscle of the patient,the at least one flange adapted to fix the lumen in place.
 9. The leadreceptacle of claim 1, further comprising: a first flange on a proximalend of the lumen for engaging with an inner surface of an innermostintercostal muscle of the patient; and, a second flange on a distal endof the lumen for engaging with an outer surface of an outermostintercostal muscle of the patient; wherein, the first flange and thesecond flange exert a force inwardly toward the middle of the lumenconfigured to fix the lumen in place.
 10. The lead receptacle of claim1, wherein the lumen is configured to be screwed into an intercostalmuscle of the patient within the intercostal space.
 11. The leadreceptacle of claim 1, wherein the lumen is configured to be pushed intoan intercostal muscle of the patient within the intercostal space. 12.The lead receptacle of claim 1, wherein the lumen is fixed into theintercostal space using a tine, a hook, a spring, or a screw.
 13. Thelead receptacle of claim 1, wherein the lumen body further comprises aseptum disposed transversely within the lumen, the septum configured toform a seal around the lead traversing through the lumen.
 14. The leadfixation receptacle of claim 1, further comprising a second lumenconfigured to traverse from an outermost side of an outermostintercostal muscle to an innermost side of an innermost intercostalmuscle.
 15. The lead fixation receptacle of claim 14, wherein the secondlumen is adapted to facilitate dispensing pharmacological agents intothe thorax of the patient.
 16. The lead receptacle of claim 1, whereinthe lumen is coated with a pharmacological agent.
 17. A method ofinsulating intercostal muscle from a cardiac lead comprising: insertinga lead receptacle into the intercostal space of a patient, the leadreceptacle comprising a lumen configured to traverse from an outermostsurface of an outermost intercostal muscle to the innermost surface ofthe innermost intercostal muscle of the patient and to support a leadtraversing through the lumen; and, fixing the lead receptacle in placein the intercostal space of the patient.
 18. The method as in claim 17,further comprising: feeding a distal end of a cardiac lead through thelead receptacle; and, positioning the distal end of the cardiac leadwithin the mediastinum of the patient to deliver electrical stimulationtherapy to a heart of the patient.
 19. The method as in claim 17,wherein the lumen is made from an electrically insulating material. 20.The method as in claim 17, wherein the lumen is coated with apharmacological agent.